A 2-Channel Carrier Telegraph System for Short Submarine Cables

A new 2-channel carrier telegraph system for short submarine telegraph cables is described. Developed specifically for the Western Union Key West-Havana cables, about 100 nautical miles in length and with attenuations up to 80 decibels at 1,000 cycles per second, it utilizes standard land-line frequency-modulation channel terminal equipment and provides excellent 50-cycle telegraph transmission on both channels without appreciably degrading the physical circuits. Depending upon the facilities available the carrier may be operated either as a metallic or a ground-return circuit.